13.2.1. Connecting a camera

Every session starts at the connect button – the plug icon at the bottom of the left toolbar, or Ctrl+E. Click it and the Viewer scans the USB serial ports for cameras and connects to the one it finds. With more than one camera attached, a dialog asks which serial port to use, preselecting your previous pick; with none, the Viewer says so and offers a recovery path for a camera that no longer enumerates (see Firmware updates and recovery).

On connect the Viewer identifies the board and reads its firmware version. A camera attached in bootloader (DFU) mode rather than as a normal serial device gets its own dialog with recovery options. On Windows the Viewer reports any USB driver problems it finds; on Linux, a permission error opening the serial port almost always means your user is not in the dialout group, and the error names the exact command that fixes it.

13.2.1.1. The status bar

Once connected, the status bar along the bottom right of the window becomes the camera’s dashboard:

• Board – the board type reported by the camera.

• Firmware Version – the running firmware version.

• Serial Port – the port the connection is using.

• Drive – the flash-drive mount point associated with the camera, when one is available.

• FPS – the rate at which frames are arriving at the Viewer. This is the preview rate, not necessarily the camera’s capture rate; newer cameras report both.

Disconnecting is forgiving. Clicking disconnect is the tidy way out, but unplugging the cable works too – the Viewer notices the camera is gone and disconnects on its own.

13.2.1.2. Auto reconnect

Tools → Auto Reconnect to OpenMV Cam makes connection fully automatic: whenever a camera appears on USB the Viewer connects to it. With one camera and one Viewer this is the convenient mode – plug the camera in and it is connected, running, and on screen.